I live in zone 5. My pitcher plants were left in the bog with no cover last winter with no problems. They are blooming right now. You should not have to "winterize" them at all. They will turn brown and ugly but will start to go green in the spring. The nursery where I get them has had them for years and does not do anything special for them in the winter either.

What kind of pitcher plants...there are ones that are more cold hardy than others.

Here's what I do...

It is true there are southern species and the one northern species S. purpurea... and, wonderfully there are many. many hybrids. Some are definitely more winter hardy than others. I have southern species like, S. rubra, flava, oreophila, alata, minor, psittacina etc., I also have purpurea and a bunch of hybrids. I am two zones warmer than you, I am growing in an artificial bog which keeps temps from great fluctuations and I heavily winter protect all my plants. Some don't need it some definitely do but they all benefit and have gotten large with extensive root systems.

I mulch w/ a couple inches of pine needles then put a few plastic pots upside down, cover with a large piece of burlap then mulch a foot or more with leaves. Sometimes I'll put some woodchips on top of that.

Yours are in pots sooooo.... I would sink the pots in the ground in late Oct. early Nov. and mulch away. Either that or put them somewhere that is cold enough for a winter dormancy but not cold enough to kill 'em w/ temps being regulated to some degree, garage? basement? that kind of thing.

Enjoy them and don't worry about it for now...... you have 4 or more months to figure it out.

Good luck!

Unless you are avid about watering them, pitcher plants do much better if they have unrestricted root systems. To wit, build them an outdoor bog garden in full sun and mulch it heavily in winter. You can also grow venus fly traps even as far north as you. Mulch is the key (and of course a properly made bog). Otherwise they will not grow as vigorously in the long run and you may very well kill them in winter, especially if they are not protected from cold. The southern species have been grown outside as far north as southern Vermont (zone 5b)successfully. PF